A significant challenge in both government and industry is the continued effort to increase the throughput of analytical applications (in particular, involving mass spectrometry), while controlling instrument costs and achieving the high resolution necessary to glean greater amounts of information about complex samples. Such information is useful in a wide variety of applications, ranging from life sciences (such as proteomics or modeling the biological functions of biomolecules in living organisms) to detection of chemical and biological agents of potential threat to national security.
Ion Mobility Spectrometry (IMS) and Field Asymmetric waveform Ion Mobility Spectrometry (FAIMS) are related gas phase techniques for rapid separation of complex mixtures and structural characterization of ions. Applications of both methods have greatly expanded since their coupling to electrospray ionization sources and mass-spectrometry. Coupling IMS to time of flight mass spectrometry (TOF MS) permitted simultaneous ion dispersion in the mobility and m/z dimensions. IMS is based on absolute ion mobility at low electric fields, while FAIMS exploits the mobility differences between high and low fields. Because of different physical mechanisms of IMS and FAIMS, the present invention couples FAIMS and IMS devices to achieve greater separation efficiency (resolving power). An extremely high ion separation speed of both FAIMS and IMS techniques makes this invention suitable for high throughput sample analyses. The general concept of the IMS system used in the present invention has been described and claimed in the U.S. Pat. No. 6,818,890, titled “High Performance Ion Mobility Spectrometry Using Hourglass Electrodynamic Funnel and Internal Ion Funnel” and is hereby explicitly incorporated into this disclosure by this reference.